State change devices for switched electrical receptacles

ABSTRACT

A state change device may be electrically connected to a switched receptacle, or to both the switched and unswitched receptacles, of an outlet. The state change device may generate a change of state signal when power is applied to, or removed from, the switched receptacle. The state change device may wirelessly communicate the signal. The state change device may include a load control circuit that may be configured to control the amount of power delivered to an electrical load that is electrically connected to the state change device. The state change device may receive commands directed to the load control circuit. The state change device may be deployed in a load control system and may operate as a control entity, such that the state change device may issue commands to one or more load control devices, responsive to the application or removal of power at the switched receptacle.

BACKGROUND

Electrical loads, such as lamps, ceiling lighting fixtures, thermostats,shades, etc., may be controlled using load control devices. Such loadcontrol devices may be configured for wireless communication. Forexample, a lamp may be electrically connected, for example plugged in,to such a load control device. The load control device may be, forexample, a dimmer switch configured for radio-frequency wirelesscommunication (e.g., an RF dimmer switch).

FIG. 1 depicts an example prior art lighting control system 10 thatincludes a table top RF dimmer switch 20 and a lamp 30 plugged into thedimmer switch 20, such that the dimmer switch 20 controls the amount ofpower delivered to the lamp 30. The dimmer switch 20 is electricallyconnected to an electrical circuit 40 that includes an alternatingcurrent (AC) power source 41 and an AC outlet 42 electrically connectedto the source 41. The outlet 42 includes a switched receptacle 43 and anunswitched receptacle 44. The electrical circuit 40 also includes awall-mounted switch 46 that is coupled in series electrical connectionbetween the source 41 and the switched receptacle 43.

The lamp 30 is also controlled by the wall-mounted switch 46. The dimmerswitch 20 includes a plug 22 that is plugged into the switchedreceptacle 43 and the lamp 30 includes a plug 32 that is plugged intothe plug 22 of the dimmer switch 20, such that the delivery of power tothe lamp 30 may be controlled via the wall-mounted switch 46.

The lighting control system 10 also includes a plurality of devicesconfigured to wirelessly communicate with the dimmer switch 20. Asshown, the lighting control system 10 includes an occupancy and/orvacancy sensor 50, a daylight sensor 60, and a remote control 70, suchas a remote keypad. The occupancy and/or vacancy sensor 50, daylightsensor 60, and/or remote control 70 may wirelessly communicate with thedimmer switch 20, for example to command the dimmer switch 20, using RFsignals 90.

Though a user could plug the dimmer switch 20 into the unswitchedreceptacle 44, many users may prefer to combine the functionality of thedimmer switch 20 with the ability to switch power to the lamp 30 usingthe wall-mounted switch 46.

However, control of the illustrated lighting control system 10 may becompromised when power is removed from the switched receptacle 43. Forexample, when the wall-mounted switch 46 is flipped to the off position,the dimmer switch 20 may become unresponsive to wirelessly communicatedcommands, for example commands to turn on, turn off, or dim the lamp 30,from the occupancy and/or vacancy sensor 50, the daylight sensor 60, andthe remote control 70. When the wall switch 46 is turned off, a wirelesscommunication component of the dimmer switch 20, such as a receiver, maybe unpowered and thus unable to receive the wirelessly communicatedcommands.

SUMMARY

As disclosed herein, a state change device may be configured to beelectrically connected to a switched AC receptacle of an outlet. Thestate change device may also be configured to be electrically connectedto both the switched and unswitched AC receptacles of an outlet. Thestate change device may be configured to generate a signal indicative ofa change of state when power is applied to, or removed from, theswitched receptacle. The state change device may wirelessly communicatethe signal, for example to one or more electrical devices associatedwith the state change device, for example a load control device such asa table-top dimmer switch configured for wireless communication.

The state change device may be installed and configured to operate withan existing load control system, for example an existing lightingcontrol system, without requiring electrical re-wiring. The state changedevice may allow a user of the state change device to relocate anelectrical load, such as a lighting load, that was previously pluggedinto the switched receptacle of the outlet, to the receptacle of anotheroutlet that is remote from the switched receptacle, for example anoutlet in another location within a room. The state change device mayallow operation of the relocated lighting load from the switched outlet.The state change device may be configured to control multiple electricaldevices in the existing load control system, such as multiple loadcontrol devices (e.g., multiple table top dimmer switches). The statechange device may be configured to operate with one more control devicesassociated with the existing load control system, such as one or more ofan occupancy and/or vacancy sensor, a daylight sensor, or a remotecontrol, without requiring that a new device be wired in place of thelight switch.

The state change device may include a sensing circuit configured todetect when AC power is applied to and/or removed from the switchedreceptacle, a controller, and a communications circuit configured forwireless communication. The sensing circuit may be configured to informthe controller when power is applied to and/or removed from the switchedreceptacle. The controller may be configured to generate the signal,upon being informed of the application of power to, and/or the removalof power from, the switched receptacle, and to cause the signal to betransmitted by the communication circuit. The controller may beconfigured to wait for a predetermined amount of time before causing thesignal to be transmitted.

The state change device may include a power supply configured to providepower to the sensing circuit, the controller, and the communicationscircuit. The power supply may include, for example, a capacitor. Thepower supply may be electrically connected to the unswitched receptacle.

The state change device may include a load control circuit that may beconfigured to control the amount of power delivered to an electricalload that is electrically connected to the state change device. Thestate change device may be configured to receive commands directed tothe load control circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example prior art lighting control system.

FIG. 2 depicts an example lighting control system.

FIG. 3 depicts an example state change device.

FIG. 4 depicts another example state change device.

FIG. 5 is a simplified block diagram of an example state change device.

FIG. 6 is a functional diagram illustrating operation of an examplestate change device when power is applied to a switched AC receptacle.

FIG. 7 is a functional diagram illustrating operation of an examplestate change device ice when power is removed from the switched ACreceptacle.

FIG. 8 depicts another example lighting control system.

FIG. 9 depicts another example state change device.

FIG. 10 is a simplified block diagram of another example state changedevice.

FIG. 11 is a functional diagram illustrating operation of an examplestate change device when power is applied to the switched AC receptacle.

FIG. 12 is a functional diagram illustrating operation of an examplestate change device when power is removed from the switched ACreceptacle.

FIG. 13 depicts an example lighting control system.

FIG. 14 depicts an example state change device.

FIG. 15 is a simplified block diagram of an example state change device.

DETAILED DESCRIPTION

FIG. 2 depicts an example load control system. As shown, the loadcontrol system is a lighting control system 100. The lighting controlsystem 100 includes a first load control device 110, a second loadcontrol device 120, and a device that may be referred to as a statechange device 130 or a state change controller. The state change device130 is configured to send signals to one or both of the first and secondload control devices 110, 120 via wireless communication. The statechange device 130 is plugged into a switched receptacle 143 of anelectrical outlet 142 and the first load control device 110 is pluggedinto an unswitched receptacle 144 of the outlet 142. The state changedevice 130 will be powered when a wall-mounted switch 146 that controlsthe switched receptacle 143 is in the on position. The first loadcontrol device 110 will be continuously powered by the unswitchedreceptacle 144.

As shown, the first and second load control devices 110, 120 are tabletop RF dimmer switches. The lighting control system 100 further includesa first lamp 115 electrically connected to, for example plugged into,the first load control device 110, such that the first load controldevice 110 controls the amount of power delivered to the first lamp 115.The lighting control system 100 further includes a second lamp 125electrically connected to, for example plugged into, the second loadcontrol device 120, such that the second load control device 120controls the amount of power delivered to the second lamp 125.

The state change device 130 may be configured to transmit the signals,for example, via radio-frequency (RF) communication signals 160. Thesignals may be indicative of a change of state within the lightingcontrol system 100, for example indicative of a change of state at aswitched receptacle that the state change device 130 is electricallyconnected to. Such signals may be referred to as change of statesignals, and may be interpreted by one or more devices associated withthe state change device 130, for example the first and/or second loadcontrol devices 110, 120, as indications to turn on, turn off, dim, etc.respective electrical loads electrically connected to the first and/orsecond load control devices 110, 120.

The state change device 130 and the first load control device 110 areelectrically connected to an electrical circuit 140 that includes analternating current (AC) power source 141 and an electrical outlet 142electrically connected to the AC power source 141. The outlet 142includes a switched receptacle 143 and an unswitched receptacle 144. Thestate change device 130 is electrically connected to, for exampleplugged into, the switched receptacle 143 and the first load controldevice 110 is electrically connected to, for example plugged into, theunswitched receptacle 144. The electrical circuit 140 also includes awall-mounted switch 146 that is coupled in series electrical connectionbetween the AC power source 141 and the switched receptacle 143.

Delivery of power to the state change device 130 may be controlled viathe wall-mounted switch 146. The first load control device 110 includesa plug 112 that is plugged into the unswitched receptacle 144 of theelectrical circuit 140 and the first lamp 115 includes a plug 117 thatis plugged into the plug 112 of the first load control device 110.

The state change device 130 may transmit signals responsive to deliveryor removal of power to the switched receptacle 143 of the outlet 142.When the wall-mounted switch 146 is operated from the off position tothe on position, power may be delivered to the switched receptacle 143.The state change device 130 may sense the presence of power at theswitched receptacle 143, and may transmit one or more signals, forexample via RF signals 160, to one or both of the first and second loadcontrol devices 110, 120. The signals may be indicative of a change ofstate in the lighting control system 100. The one or more signals may bereceived at one or both of the first and second load control devices110, 120. Responsive to receipt of the signals, one or both of the firstand second load control devices 110, 120 may change the state of thefirst or second lamps 115, 125, respectively. For example, the firstload control device 110 may change the state of the first lamp 115 fromoff to on and the second load control device 120 may change the state ofthe second lamp 125 from off to on.

When the wall-mounted switch 146 is operated from the on position to theoff position, power may be removed from the switched receptacle 143. Thestate change device 130 may sense the removal of power from the switchedreceptacle 143, and may transmit one or more signals, for example via RFsignals 160, to one or both of the first and second load control devices110, 120. The signals may be indicative of a change of state in thelighting control system 100. The one or more signals may be received atone or both of the first and second load control devices 110, 120.Responsive to receipt of the signals, one or both of the first andsecond load control devices 110, 120 may change the state of the firstor second lamps 115, 125, respectively. For example, the first loadcontrol device 110 may change the state of the first lamp 115 from on tooff and the second load control device 120 may change the state of thesecond lamp 125 from on to off.

The one or more signals transmitted by the state change device 130, forexample responsive to operation of the wall-mounted switch 146 from theon position to the off position or from the off position to the onposition, are not limited to indicating a change of state in thelighting control system 100. For example, one or more signalstransmitted by the state change device 130, for example responsive tooperation of the wall-mounted switch 146, may be indicative of a loadcontrol scene (e.g., a lighting scene or preset) to be applied to one ormore electrical loads (e.g., the first and second lamps 115, 125) of thelighting control system 100. A lighting scene may include respectivepredetermined states that are to be assumed by one or more lightingloads of the lighting control system 100. For example, a lighting scenemay include one or both of the first and second lamps 115, 125 in theoff state, may include one or both of the first and second lamps 115,125 in the on state, may include one or both of the first and secondlamps 115, 125 dimmed to a select dimming level, or any combination ofthereof.

Respective signals indicative of one or more load control scenes may betransmitted, for example, in accordance with a number of times that thewall-mounted switch 146 is operated from one state to the other (e.g.,from off to on or from on to off) within a prescribed amount of time.For example, the state change device 130 may be configured to generateand transmit one or more change of state signals if the wall-mountedswitch 146 is operated from one state to the other once during theprescribed amount of time, may be configured to generate and transmitone or more signals indicative of a first lighting scene if thewall-mounted switch 146 is operated from one state to the other twiceduring the prescribed amount of time, may be configured to generate andtransmit one or more signals indicative of a second lighting scene ifthe wall-mounted switch 146 is operated from one state to the otherthree times during the prescribed amount of time, and so on.

The state change device 130 may be deployed in a load control systemthat includes multiple load control devices and/or associated electricalloads, such as the lighting control system 100 depicted in FIG. 2. Oneof the load control devices, for example the first load control device110 or the second load control device 120, may be configured to operateas a control entity, such as a master device, within the lightingcontrol system 100.

The master device, or master, may operate to at least partially controlfunctionality of the other load control devices of the load controlsystem. The other load control devices of the load control system may beconfigured to assume subservient roles to the master device, such thatthe subservient devices will perform commands issued by the master. Itshould be appreciated that if the load control system includes only oneload control device, the load control system may not include a master.

One of the load control devices may be designated as the master, forexample by a user of the load control system. Alternatively, one of theload control devices may assume the role of the master. For example,upon association with the load control system, a load control device maypoll the other load control devices of the load control system, forexample via broadcast, to determine if the load control system currentlyhas a master. If the polling load control device does not receive ananswer that another device of the load control system is the master, thepolling load control device may assume the role of the master in theload control system.

The master load control device may be configured to observe and/orrecord present state information pertaining to one or more subservientload control devices of the load control system. In an example, withreference to the lighting control system 100 shown in FIG. 2, the firstload control device 110 may assume the role of master and the secondload control device 120 may assume a subservient role to the first loadcontrol device 110, such that the first load control device 110 is ableto at least partially control operation of the second load controldevice 120. The first load control device 110 may observe and/or recordpresent state information, for example last known state information,pertaining to the second load control device 120 and/or to an electricalload electrically connected to the second load control device 120, forexample information pertaining to a last known state of the second lamp125 (e.g., whether the second lamp 125 is on or off).

The first load control device 110, in the role of master in the lightingcontrol system 100, may be configured such that if at least one lightingload, for example the first lamp 115 or the second lamp 125, is in an onstate when the state change device 130 transmits one or more change ofstate signals, one or more of the other lighting loads of the lightingcontrol system 100 (e.g., each of the other lighting loads) will beoperated from the on state to the off state or left in the off state.For example, if the first lamp 115 is off and the second lamp 125 is onwhen the wall-mounted switch 146 is operated, the state change device130 will transmit one or more change of state signals that may bereceived by the first and second load control devices 110, 120. Thesecond load control device 120 may ignore the one or more change ofstate signals from the state change device 130, for example inaccordance with the subservient role the second load control device 120has with respect to the first load control device 110. When the one ormore change of state signals are received by the first load controldevice 110, the first load control device 110 will not change the stateof the first lamp 115 and may forward the one or more change of statesignals to the second load control device 120. Alternatively, the firstload control device 110 may reference the last known state informationpertaining to the second load control device 120, and may transmit anappropriate command, for example a command to turn the second lamp 125off, to the second load control device 120. The second load controldevice 120, upon receipt of the forwarded change of state signal or thecommand, will change the state of the second lamp 125 from on to off.

Alternatively, first load control device 110, in the role of master inthe lighting control system 100, may be configured to maintainsynchronization of the lighting loads of the lighting control system100. For example, if the state of the first lamp 115 is changed locallyat the first load control device 110, the first load control device 110may transmit a command to the second load control device 120 that willcause second load control device 120 to change the state of the secondlamp 125, thus keeping the states of the first and second lamps 115,125, synced to one another. If the state of the second lamp 125 ischanged locally at the second load control device 120, the first loadcontrol device 110 may change the state of the first lamp 115, thuskeeping the states of the first and second lamps 115, 125, synced to oneanother.

When the wall-mounted switch 146 is operated, the state change device130 will transmit one or more change of state signals that may bereceived by the first and second load control devices 110, 120. Thesecond load control device 120 may ignore the one or more change ofstate signals from the state change device 130, for example inaccordance with the subservient role the second load control device 120has with respect to the first load control device 110. When the one ormore change of state signals are received by the first load controldevice 110, the first load control device 110 will change the state ofthe first lamp 115, for example from on to off or from off to on, andmay forward the one or more change of state signals to the second loadcontrol device 120. Alternatively, the first load control device 110 maytransmit an appropriate command, for example to turn the second lamp 125on or off, to the second load control device 120. The second loadcontrol device 120, upon receipt of the forwarded change of state signalor the command, will change the state of the second lamp 125, forexample from on to off or from off to on, such that the states of thefirst and second lamps 115, 125 are kept in sync.

The role of master in a load control system in which the state changedevice 130 is deployed, for example the lighting control system 100,need not be fulfilled by a load control device of the load controlsystem, for example the first or second load control devices 110, 120.Such a load control system may include another device configured tofulfill the role of master, for example a central controller, a mainrepeater, or the like. In such a configuration, one or more load controldevices of the load control system, for example the first and secondload control devices 110, 120, may be configured to assume subservientroles to the master, and the master may be configured to observe and/orrecord present state information pertaining to the subservient loadcontrol devices of the load control system. The subservient load controldevices may be configured to ignore change of state signals transmittedby the state change device 130 and the master may be configured toforward change of state signals received from the state change device130 to the subservient load control devices, or may, upon receipt of oneor more change of state signals from the state change device 130,transmit appropriate commands to the subservient load control devices.

A load control system in which the state change device 130 is deployed(e.g., the lighting control system 100) need not include a centralcontrol entity, such as a master. One or more load control devicesassociated with the load control system (e.g., for example the first andsecond load control devices 110, 120) may be configured to be aware ofpresent state information pertaining to the other load control devicesof the lighting control system 100. For example, the first load controldevice 110 may be configured to be aware of whether the second lamp 125electrically connected to the second load control device 120 is on oroff. Similarly, the second load control device 120 may be configured tobe aware of whether the first lamp 115 electrically connected to thefirst load control device 110 is on or off. In such a configuration, thefirst and second load control devices 110, 120 may operate to ensurethat the first and second lamps 115, 125 are kept in sync with oneanother, for example responsive to one or more change of state signalstransmitted by the state change device 130.

The second load control device 120 is electrically connected to anelectrical circuit 150 that includes an alternating current (AC) powersource 151 and an electrical outlet 152 electrically connected to the ACpower source 151. The AC power source 151 may be, for example, the ACpower source 141. The outlet 152 includes two unswitched receptacles154. The second load control device 120 includes a plug 122 that isplugged into one of the unswitched receptacles 154 of the outlet 152 andthe second lamp 125 includes a plug 127 that is plugged into the plug122 of the second load control device 120. The lighting control system100 need not include the illustrated second load control device 120and/or the second lamp 125. Furthermore, lighting control system 100 mayinclude more or fewer load control devices that are associated with, forexample configured to be controlled by, the state change device 130.Each of the more or fewer load control devices may be electricallyconnected to respective electrical devices.

The lighting control system 100 may also include one or more otherdevices configured to wirelessly communicate with one or both of thefirst and second load control devices 110, 120. As shown, the lightingcontrol system 100 includes an occupancy and/or vacancy sensor 170, adaylight sensor 175, and a remote control 180, such as a remote keypad.The occupancy and/or vacancy sensor 170, the daylight sensor 175, and/orthe remote control 180 may wirelessly communicate with one or both ofthe first and second load control devices 110, 120, for example using RFsignals 160. For example, the occupancy and/or vacancy sensor 170, thedaylight sensor 175, and/or the remote control 180 may wirelesslycommunicate commands to one or both of the first and second load controldevices 110, 120 (e.g., turn on, turn off, or dim one or both of thefirst lamp 115 or the second lamp 125).

FIG. 3 depicts an example state change device 230. The state changedevice 230 may be deployed, for example, as the state change device 130as depicted in FIG. 2. The state change device 230 includes a housing232 that may be made of any suitable material, such as plastic. Thehousing 232 may enclose one or more electrical components of the statechange device 230. The state change device 230 may be configured to beplaced into electrical communication with an electrical circuit, forexample the electrical circuit 140. As shown, the state change device230 includes a plug that includes a pair of blades 234 that protrudeinward from the housing 232 and are configured to be inserted into areceptacle of a standard electrical outlet, for example the switchedreceptacle 143 of the outlet 142. The state change device 230 may definea control interface that is accessible to a user of the state changedevice 230. For example, the illustrated state change device 230includes a plurality of buttons 236 that protrude through a side of thehousing 232. Each of the buttons 236 may be associated with one or morefunctions of the state change device 230.

FIG. 4 depicts another example state change device 330 that may be usedfor example, in the lighting control system 100. For example, the statechange device 330 may be electrically connected to, for example screwedinto, a socket of the first lamp 115 or the second lamp 125. The statechange device 330 includes a housing 332 that may be made of anysuitable material, such as plastic. The housing 332 may enclose one ormore electrical components of the state change device 330. The statechange device 330 may be configured to be placed into electricalcommunication with an electrical circuit. As shown, the state changedevice 330 includes a terminal assembly 331 that protrudes forwardthrough the housing 332 and is configured to be screwed into a standardlight socket. The terminal assembly 331 includes a side terminal 334, abase terminal 336 and an insulator 335 electrically isolates the sideterminal 334 from the base terminal 336. The state change device 330defines a socket 337 that extends into an end of the housing 332opposite the terminal assembly 331. The socket 337 may be configured toreceive a standard light bulb, for example. The state change device 330may define a user interface that is accessible to a user of the statechange device 330. For example, the illustrated state change device 330includes a plurality of buttons 338 that protrude through a side of thehousing 332. Each of the buttons 338 may be associated with one or morefunctions of the state change device 330.

FIG. 5 is a simplified block diagram of an example state change device400 that may be implemented as, for example, the state change device 130illustrated in FIG. 2, the state change device 230 illustrated in FIG.3, or the state change device 330 illustrated in FIG. 4. As shown, thestate change device 400 includes hot and neutral terminals 402, 404 thatare configured to be electrically connected to a receptacle of an outletpowered by an alternating current (AC) power source 406. The receptacleis a switched receptacle that may be controlled by a switch 408, such asa wall-mounted switch.

The state change device 400 includes a control circuit, for example acontroller 410, that is configured to control one or more functions ofthe state change device 400. The controller 410 may include one or morecomponents, such as processors (e.g., microprocessors),microcontrollers, integrated circuits (e.g., field programmable gatearrays), or the like, in any combination. For example, the controller410 may include a processor (not shown) that may executecomputer-executable instructions in order to control one or morefunctional aspects of the state change device 400.

The state change device 400 includes a power sensing circuit 412 that isconfigured to sense when power is applied to the state change device400, for example when the switch 408 is closed such that power isdelivered from the AC power source 406 to the state change device 400.The power sensing circuit 412 may provide one or more signals to thecontroller 410 that are indicative of whether power is applied to (e.g.,present at) a switched receptacle to which the state change device 400is electrically connected, for example the switched receptacle 143 ofthe outlet 142. For example, the power sensing circuit 412 may provide asignal to the controller 410 when the switch 408 is operated from theopen position to the closed position. The signal may be indicative ofpower being applied at the switched receptacle 143. The power sensingcircuit 412 may provide a signal to the controller 410 when the switch408 is operated from the closed position to the open position. Thesignal may be indicative of power being removed from the switchedreceptacle 143 of the outlet 142, for example.

The state change device 400 includes a memory 414. The memory 414 may becommunicatively coupled to the controller 410 and may operate to storeinformation such as computer-executable instructions, configurationsettings associated with operation of the state change device 400, alast known state of one or more devices associated with the state changedevice 400, or the like. The memory 414 may include any componentsuitable for storing the information. For example, the memory 414 mayinclude one or more components of volatile and/or non-volatile memory,in any combination. The memory 414 may be internal and/or external withrespect to the controller 410. For example, the memory 414 and thecontroller 410 may be integrated within a microchip. During operation ofthe state change device 400, the controller 410 may store and/orretrieve information, for instance the computer-executable instructions,from the memory 414. It should be appreciated that functionality of thecontroller 410 may include any combination of hardware, firmware, and/orsoftware.

The state change device 400 includes a control interface 416 that may beoperated, for example, by a user of the state change device 400. Asshown, the control interface 416 includes one or more actuators 418 thatmay be, for example, the buttons 236 of the state change device 230 orthe buttons 338 of the state change device 330, and one or more visualindicators 420, for example light emitting diodes (LEDs). Each actuator418 may be associated with a respective visual indicator 420, forexample. The control interface 416 may provide one or more inputs to thecontroller 410, for example a signal indicative of actuation of acorresponding one of the actuators 418. The control interface 416 mayreceive one or more inputs from the controller 410, for example commandsto cause one or more of the visual indicators 420 to illuminate.

The state change device 400 includes a wireless communication circuit422 that is communicatively coupled to the controller 410. The wirelesscommunication circuit 422 may include, for example, an RF communicationcircuit coupled to an antenna 424. The wireless communication circuit422 may include one or more components operable for the transmissionand/or reception of information that may include signals and/or data.For instance, the wireless communication circuit 422 may include an RFtransceiver, an RF transmitter, an RF receiver, an infrared (IR)transmitter, an IR receiver, a modem, and/or the like. The controller410 may be configured to transmit information via the wirelesscommunication circuit 422, for example a signal indicative of a changeof state of the state change device 400, such as the application ofpower to or the removal of power from a switched receptacle to which thestate change device 400 is electrically connected. The wirelesscommunication circuit 422 may be configured with capabilities totransmit information in accordance with one or more communicationschemes. For example, the wireless communication circuit 422 may beconfigured to be capable of transmitting information via RFcommunication.

The state change device 400 includes a power supply 426 configured tosupply power to one or more components of the state change device 400,for instance when the switch 408 is closed such that power is deliveredto the switched receptacle 143 of the outlet 142. The power supply 426may be configured to accumulate and store electricity when a voltageassociated with the AC power source 406 is dropped across the statechange device 400, for instance when power is delivered to the switchedreceptacle 143. The power supply 426 may be a transitory power supply,such that power may not be continuously supplied by the power supply426. The power supply 426 may be, for example, a capacitor that ischarged when power is delivered to the switched receptacle 143. Thestored electricity may be used to supply power to one or more componentsof the state change device 400, for example the controller 410, thepower sensing circuit 412, and/or the wireless communication circuit422. The capacitor may be configured to store sufficient electricity forthe controller 410 to cause a change of state signal to be transmittedby the wireless communication circuit 422 when the controller 410receives a signal from the power sensing circuit 412 indicating thatpower has been removed from the switched receptacle 143. Alternatively,the power supply 426 may be a semi-permanent, removable power supplycapable of continuously providing power to components of the statechange device 400, for example one or more batteries.

It should be appreciated that one or more of the above-describedcomponents of the state change device 400, such as the power sensingcircuit 412, the memory 414, and/or the wireless communication circuit422, may be at least partially integrated with (e.g., completelyintegrated with) the controller 410, for example within a singlemicrochip, such as an integrated circuit.

FIG. 6 is a functional diagram illustrating an example operation process500 of a state change device, for example the state change devices 130,230, 330, or 400, when power is applied to a switched AC receptacle towhich the state change device is electrically connected, for example theswitched receptacle 143 of the outlet 142.

The operation process 500 begins at 502, when power is applied to theswitched receptacle to which the state change device, for example thestate change device 400, is electrically connected. At 504, the powersupply 426 of the state change device 400 charges. At 506, the circuitryof the state change device 400, for example the controller 410, thepower sensing circuit 412, and/or the wireless communication circuit 422are powered up. The circuitry of the state change device 400 may receivepower from, for example, the power supply 426. The controller 410 may,for example at 506, initiate a startup routine. The startup routine maybe initiated each time the controller circuitry is powered up, forexample each time power is applied to the switched receptacle to whichthe state change device is electrically connected.

At 508, the controller 410 may trigger the wireless communicationcircuit 422 to transmit a signal indicative of a change of state of thestate change device 400. The signal may indicate, for example, that thestate of the state change device 400 has changed from an off state to anon state. The controller 410 may cause the signal to be transmitted, forexample, as part of the startup routine of the state change device 400.The controller 410 may cause the wireless communication circuit 422 totransmit the signal via the antenna 424. The controller 410 may causethe wireless communication circuit 422 to transmit the signal one ormore times, for example in accordance with a configuration setting thatis stored in the memory 414 and retrieved by the controller 410.

The one or more signals may be broadcast to one or more devices that areassociated with the state change device 400. For example, with referenceto the example lighting control system 100 depicted in FIG. 2, the statechange device 130 may broadcast the signal to the first and second loadcontrol devices 110, 120 via RF signals 160.

Alternatively, subsequent to 506 and prior to 508, for example, thepower sensing circuit 412 may determine that power has been supplied tothe switched receptacle. The power sensing circuit 412 may detect thepresence of power at the switched receptacle. The power sensing circuit412 may, responsive to detecting power at the switched receptacle,provide a signal to the controller 410 that indicates power has beenapplied at the switched receptacle. The power sensing circuit 412 maycontinue to send signals to the controller 410 to indicate the continuedpresence of power at the switched receptacle. The controller 410 mayreceive the one or more signals from the power sensing circuit 412indicating that power has been applied at the switched receptacle. Thecontroller 410 may then wait until a predetermined amount of time haselapsed. The predetermined amount of time may be a state of changethreshold time, upon expiration of which the controller 410 may triggerthe wireless communication circuit 422 to transmit the signal indicativeof a change of state of the state change device 400.

At 510, upon receiving the signal, the first and second load controldevices 110, 120 may determine whether to change the states ofrespective electrical loads electrically connected to the first andsecond load control devices 110, 120, for example the first and secondlamps 115, 125. For example, the first and second load control devices110, 120 may receive one or more forwarded change of state signalstransmitted by the state change device 130, or may receive respectivecommands, for example transmitted by a master device in the lightingcontrol system 100 responsive to one or more change of state signalstransmitted by the state change device 130. The commands may, forexample, direct the first and second load control devices 110, 120 tochange the states of the first and second lamps 115, 125. Alternatively,the determination may be based, for example, upon a last known state ofthe first and second lamps 115, 125. Based upon the determinations, thefirst and second load control devices 110, 120, may initiate statechanges for the first and second lamps 115, 125. For example, the firstload control device 110 may cause the first lamp 115 to operate from anoff state to an on state and the second load control device 120 maycause the second lamp 125 to operate from an off state to an on state.

At 512, the one or more associated devices, for example the first andsecond load control devices 110, 120, may forward the signal to one ormore other devices associated with the first and second load controldevices 110, 120. For example, if the first load control device 110 isoperating as a master of the lighting control system 100, the first loadcontrol device 110 may forward the signal to the second load controldevice 120 and/or to one or more other devices associated with thelighting control system 100, or may issue a command to the second loadcontrol device 120 to change the state of the second lamp 125 (e.g.,turn the second lamp 125 on, turn the second lamp 125 off, or dim thesecond lamp 125). Similarly, if the second load control device 120 isoperating as a master of the lighting control system 100, the secondload control device 120 may forward the signal to the first load controldevice 110 and/or to one or more other devices associated with thelighting control system 100, or may issue a command to the first loadcontrol device 110 to change the state of the first lamp 115 (e.g., turnthe first lamp 115 on, turn the first lamp 115 off, or dim the firstlamp 115). After 512, the operation process 500 may conclude. It shouldbe appreciated that 512 is optional, for example in accordance withwhether or not one of the first or second load control devices 110, 120is operating as a master of the lighting control system 100. Forexample, if neither of the first or second load control devices 110, 120are operating as a master in the lighting control system 100, theoperation process 500 may conclude after 510, when the first and secondload control devices 110, 120 have received and/or processed the signal.

FIG. 7 is a functional diagram illustrating an example operation process600 of a state change device, for example the state change devices 130,230, 330, or 400, when power is removed from a switched AC receptacle towhich the state change device is electrically connected, for example theswitched receptacle 143 of the outlet 142.

The operation process 600 begins at 602, when power is removed from theswitched receptacle to which the state change device, for example thestate change device 400, is electrically connected. At 604, the powersensing circuit 412 determines that power has been removed from theswitched receptacle. The power sensing circuit 412 may detect theabsence of power at the switched receptacle. The power sensing circuit412 may, responsive to detecting the lack of power at the switchedreceptacle, provide a signal to the controller 410 that indicates powerhas been removed from the switched receptacle. Alternatively, the powersensing circuit 412 may cease sending signals to the controller 410 thatindicate the continued presence of power at the switched receptacle.

At 606, the controller 410 may receive one or more signals from thepower sensing circuit 412 indicating that power has been removed fromthe switched receptacle. The controller 410 may then determine whetherpower has actually been removed or whether a line disturbance hasoccurred. The controller 410 may make this determination, for example,by waiting for a predetermined interval of time and listening for one ormore signals from the power sensing circuit 412 that indicate that powerhas been applied at the switched receptacle. If the controller 410receives one or more such signals, the controller 410 may determine thata line disturbance has occurred and the operation process 600 mayconclude. If predetermined interval expires and the controller 410 hasnot received one or more such signals, the controller 410 may determinethat power has been removed from the switched receptacle.

At 608, after determining that power has been removed from the switchedreceptacle, the controller 410 may trigger the wireless communicationcircuit 422 to transmit a signal indicative of a change of state of thestate change device 400. The signal may indicate, for example, that thestate of the state change device 400 has changed from an on state to anoff state. The controller 410 may cause the wireless communicationcircuit 422 to transmit the signal via the antenna 424. The controller410 may cause the wireless communication circuit 422 to transmit thesignal one or more times, for example in accordance with a configurationsetting that is stored in the memory 414 and retrieved by the controller410. The controller 410 and the wireless communication circuit 422 mayuse electricity stored in the power supply 426 to transmit the one ormore signals.

The one or more signals may be broadcast to one or more devices that areassociated with the state change device 400. For example, with referenceto the example lighting control system 100 depicted in FIG. 2, the statechange device 130 may broadcast the signal to the first and second loadcontrol devices 110, 120 via RF signals 160.

At 610, upon receiving the signal, the first and second load controldevices 110, 120 may determine whether to change the states ofrespective electrical loads electrically connected to the first andsecond load control devices 110, 120, for example the first and secondlamps 115, 125. For example, the first and second load control devices110, 120 may receive one or more forwarded change of state signalstransmitted by the state change device 130, or may receive respectivecommands, for example transmitted by a master device in the lightingcontrol system 100 responsive to one or more change of state signalstransmitted by the state change device 130. The commands may, forexample, direct the first and second load control devices 110, 120 tochange the states of the first and second lamps 115, 125. Alternatively,the determination may be based, for example, upon a last known state ofthe first and second lamps 115, 125. Based upon the determinations, thefirst and second load control devices 110, 120, may initiate statechanges for the first and second lamps 115, 125. For example, the firstload control device 110 may cause the first lamp 115 to operate from anon state to an off state and the second load control device 120 maycause the second lamp 125 to operate from an on state to an off state.

At 612, the one or more associated devices, for example the first andsecond load control devices 110, 120, may forward the signal to one ormore other devices associated with the first and second load controldevices 110, 120. For example, if the first load control device 110 isoperating as a master of the lighting control system 100, the first loadcontrol device 110 may forward the signal to the second load controldevice 120 and/or to one or more other devices associated with thelighting control system 100, or may issue a command to the second loadcontrol device 120 to change the state of the second lamp 125 (e.g.,turn the second lamp 125 on, turn the second lamp 125 off, or dim thesecond lamp 125). Similarly, if the second load control device 120 isoperating as a master of the lighting control system 100, the secondload control device 120 may forward the signal to the first load controldevice 110 and/or to one or more other devices associated with thelighting control system 100, or may issue a command to the first loadcontrol device 110 to change the state of the first lamp 115 (e.g., turnthe first lamp 115 on, turn the first lamp 115 off, or dim the firstlamp 115). After 612, the operation process 600 may conclude. It shouldbe appreciated that 612 is optional, for example in accordance withwhether or not one of the first or second load control devices 110, 120is operating as a master of the lighting control system 100. Forexample, if neither of the first or second load control devices 110, 120are operating as a master in the lighting control system 100, theoperation process 600 may conclude after 610, when the first and secondload control devices 110, 120 have received and/or processed the signal.

FIG. 8 depicts an example load control system. As shown, the loadcontrol system is a lighting control system 700. The lighting controlsystem 700 includes a first load control device 710, a second loadcontrol device 720, and a device that may be referred to as a statechange device 730 or a state change controller. The state change device730 is configured to send signals to one or both of the first and secondload control devices 710, 720 via wireless communication. The statechange device 730 is plugged into both the switched receptacle 743 andthe unswitched receptacle 744 of an outlet 742. The state change device730 will be continuously powered by the unswitched receptacle 744. Thestate change device 730 includes a pair of unswitched receptacles 732.The first load control device 710 is plugged into one of the unswitchedreceptacles 732.

As shown, the first and second load control devices 710, 720 are tabletop RF dimmer switches. The lighting control system 700 further includesa first lamp 715 electrically connected to, for example plugged into,the first load control device 710, such that the first load controldevice 710 controls the amount of power delivered to the first lamp 715.The lighting control system 700 further includes a second lamp 725electrically connected to, for example plugged into, the second loadcontrol device 720, such that the second load control device 720controls the amount of power delivered to the second lamp 725.

The state change device 730 may be configured to transmit signals, forexample, via radio-frequency (RF) communication signals 760. The statechange device 730 may transmit signals to one or both of the first andsecond load control devices 710, 720, for example. The signals may beindicative of a change of state within the lighting control system 700,for example indicative of a change of state at a switched receptaclethat the state change device 730 is electrically connected to. Suchsignals may be referred to as change of state signals, and may beinterpreted by one or more devices associated with the state changedevice 730, for example the first and/or second load control devices710, 720, as indications to turn on, turn off, dim, etc. respectiveelectrical loads electrically connected to the first and/or second loadcontrol devices 710, 720.

The state change device 730 and the first load control device 710 areelectrically connected to an electrical circuit 740 that includes analternating current (AC) power source 741 and an electrical outlet 742electrically connected to the AC power source 741. The outlet 742includes a switched receptacle 743 and an unswitched receptacle 744. Thestate change device 730 is electrically connected to, for exampleplugged into, the switched receptacle 743 and the unswitched receptacle744. The electrical circuit 740 also includes a wall-mounted switch 746that is coupled in series electrical connection between the AC powersource 741 and the switched receptacle 743.

The state change device 730 may derive power from the unswitchedreceptacle 744, regardless of whether power is applied to the switchedreceptacle 743, for example whether the wall-mounted switch 746 is inthe on position or the off position. The state change device 730includes a pair of unswitched receptacles 732. The state change device730 is not limited to two receptacles as illustrated, and may includemore or fewer than two receptacles. The first load control device 710includes a plug 712 that is plugged into one of the unswitchedreceptacles 732 of the state change device 730 and the first lamp 715includes a plug 717 that is plugged into the plug 712 of the first loadcontrol device 710, such that the first load control device 710 will becontinuously powered by the unswitched receptacle 732.

The state change device 730 may transmit signals responsive to deliveryor removal of power to the switched receptacle 743 of the outlet 742.When the wall-mounted switch 746 is operated from the off position tothe on position, power may be delivered to the switched receptacle 743.The state change device 730 may sense the presence of power at theswitched receptacle 743, and may transmit one or more signals, forexample via RF signals 760, to one or both of the first and second loadcontrol devices 710, 720. The signals may be indicative of a change ofstate in the lighting control system 700. The one or more signals may bereceived at one or both of the first and second load control devices710, 720. Responsive to receipt of the signals, one or both of the firstand second load control devices 710, 720 may change the state of thefirst or second lamps 715, 725, respectively. For example, the firstload control device 710 may change the state of the first lamp 715 fromoff to on and the second load control device 720 may change the state ofthe second lamp 725 from off to on.

When the wall-mounted switch 746 is operated from the on position to theoff position, power may be removed from the switched receptacle 743. Thestate change device 730 may sense the removal of power from the switchedreceptacle 743, and may transmit one or more signals, for example via RFsignals 760, to one or both of the first and second load control devices710, 720. The signals may be indicative of a change of state in thelighting control system 700. The one or more signals may be received atone or both of the first and second load control devices 710, 720.Responsive to receipt of the signals, one or both of the first andsecond load control devices 710, 720 may change the state of the firstor second lamps 715, 725, respectively. For example, the first loadcontrol device 710 may change the state of the first lamp 715 from on tooff and the second load control device 720 may change the state of thesecond lamp 725 from on to off.

The one or more signals transmitted by the state change device 730, forexample responsive to operation of the wall-mounted switch 746 from theon position to the off position or from the off position to the onposition, are not limited to indicating a change of state in thelighting control system 700. For example, one or more signalstransmitted by the state change device 730, for example responsive tooperation of the wall-mounted switch 746, may be indicative of a loadcontrol scene (e.g., a lighting scene or preset) to be applied to one ormore electrical loads (e.g., the first and second lamps 715, 725) of thelighting control system 700. A lighting scene may include respectivepredetermined states that are to be assumed by one or more lightingloads of the lighting control system 700. For example, a lighting scenemay include one or both of the first and second lamps 715, 725 in theoff state, may include one or both of the first and second lamps 715,725 in the on state, may include one or both of the first and secondlamps 715, 725 dimmed to a select dimming level, or any combination ofthereof.

Respective signals indicative of one or more load control scenes may betransmitted, for example, in accordance with a number of times that thewall-mounted switch 746 is operated from one state to the other (e.g.,from off to on or from on to off) within a prescribed amount of time.For example, the state change device 730 may be configured to generateand transmit one or more change of state signals if the wall-mountedswitch 746 is operated from one state to the other once during theprescribed amount of time, may be configured to generate and transmitone or more signals indicative of a first lighting scene if thewall-mounted switch 746 is operated from one state to the other twiceduring the prescribed amount of time, may be configured to generate andtransmit one or more signals indicative of a second lighting scene ifthe wall-mounted switch 746 is operated from one state to the otherthree times during the prescribed amount of time, and so on.

The state change device 730 may be deployed in a load control systemthat includes multiple load control devices and/or associated electricalloads, such as the lighting control system 700 depicted in FIG. 8. Oneof the load control devices, for example the first load control device710 or the second load control device 720, may be configured to operateas a control entity, such as a master device, within the lightingcontrol system 700.

The master device, or master, may operate to at least partially controlfunctionality of the other load control devices of the load controlsystem. The other load control devices of the load control system may beconfigured to assume subservient roles to the master device, such thatthe subservient devices will perform commands issued by the master. Itshould be appreciated that if the load control system includes only oneload control device, the load control system may not include a master.

One of the load control devices may be designated as the master, forexample by a user of the load control system. Alternatively, one of theload control devices may assume the role of the master. For example,upon association with the load control system, a load control device maypoll the other load control devices of the load control system, forexample via broadcast, to determine if the load control system currentlyhas a master. If the polling load control device does not receive ananswer that another device of the load control system is the master, thepolling load control device may assume the role of the master in theload control system.

The master load control device may be configured to observe and/orrecord present state information pertaining to one or more subservientload control devices of the load control system. In an example, withreference to the lighting control system 700 shown in FIG. 8, the firstload control device 710 may assume the role of master and the secondload control device 720 may assume a subservient role to the first loadcontrol device 710, such that the first load control device 710 is ableto at least partially control operation of the second load controldevice 720. The first load control device 710 may observe and/or recordpresent state information, for example last known state information,pertaining to the second load control device 720 and/or to an electricalload electrically connected to the second load control device 720, forexample information pertaining to a last known state of the second lamp725 (e.g., whether the second lamp 725 is on or off).

The first load control device 710, in the role of master in the lightingcontrol system 700, may be configured such that if at least one lightingload, for example the first lamp 715 or the second lamp 725, is in an onstate when the state change device 730 transmits one or more change ofstate signals, one or more of the other lighting loads of the lightingcontrol system 700 (e.g., each of the other lighting loads) will beoperated from the on state to the off state or left in the off state.For example, if the first lamp 715 is off and the second lamp 725 is onwhen the wall-mounted switch 746 is operated, the state change device730 will transmit one or more change of state signals that may bereceived by the first and second load control devices 710, 720. Thesecond load control device 720 may ignore the one or more change ofstate signals from the state change device 730, for example inaccordance with the subservient role the second load control device 720has with respect to the first load control device 710. When the one ormore change of state signals are received by the first load controldevice 710, the first load control device 710 will not change the stateof the first lamp 715 and may forward the one or more change of statesignals to the second load control device 720. Alternatively, the firstload control device 710 may reference the last known state informationpertaining to the second load control device 720, and may transmit anappropriate command, for example a command to turn the second lamp 725off, to the second load control device 720. The second load controldevice 720, upon receipt of the forwarded one or more change of statesignals or the command, will change the state of the second lamp 725from on to off.

Alternatively, first load control device 710, in the role of master inthe lighting control system 700, may be configured to maintainsynchronization of the lighting loads of the lighting control system700. For example, if the state of the first lamp 715 is changed locallyat the first load control device 710, the first load control device 710may transmit a command to the second load control device 720 that willcause second load control device 720 to change the state of the secondlamp 725, thus keeping the states of the first and second lamps 715,725, synced to one another. If the state of the second lamp 725 ischanged locally at the second load control device 720, the first loadcontrol device 710 may change the state of the first lamp 715, thuskeeping the states of the first and second lamps 715, 725, synced to oneanother.

When the wall-mounted switch 746 is operated, the state change device730 will transmit one or more change of state signals that may bereceived by the first and second load control devices 710, 720. Thesecond load control device 720 may ignore the one or more change ofstate signals from the state change device 730, for example inaccordance with the subservient role the second load control device 720has with respect to the first load control device 710. When the one ormore change of state signals are received by the first load controldevice 710, the first load control device 710 will change the state ofthe first lamp 715, for example from on to off or from off to on, andmay forward the one or more change of state signals to the second loadcontrol device 720. Alternatively, the first load control device 710 maytransmit an appropriate command, for example to turn the second lamp 725on or off, to the second load control device 720. The second loadcontrol device 720, upon receipt of the forwarded change of state signalor the command, will change the state of the second lamp 725, forexample from on to off or from off to on, such that the states of thefirst and second lamps 715, 725 are kept in sync.

The role of master in a load control system in which the state changedevice 730 is deployed, for example the lighting control system 700,need not be fulfilled by a load control device of the load controlsystem, for example the first or second load control devices 710, 720.Such a load control system may include another device configured tofulfill the role of master, for example a central controller, a mainrepeater, or the like. In such a configuration, one or more load controldevices of the load control system, for example the first and secondload control devices 710, 720, may be configured to assume subservientroles to the master, and the master may be configured to observe and/orrecord present state information pertaining to the subservient loadcontrol devices of the load control system. The subservient load controldevices may be configured to ignore change of state signals transmittedby the state change device 730 and the master may be configured toforward change of state signals received from the state change device730 to the subservient load control devices, or may, upon receipt of oneor more change of state signals from the state change device 730,transmit appropriate commands to the subservient load control devices.

A load control system in which the state change device 730 is deployed,for example the lighting control system 700, need not include a centralcontrol entity, such as a master. For example, one or more load controldevices associated with the load control system, for example the firstand second load control devices 710, 720, may be configured to be awareof present state information pertaining to the other load controldevices of the lighting control system 700. For example, the first loadcontrol device 710 may be configured to be aware of whether the secondlamp 725 electrically connected to the second load control device 720 ison or off. Similarly, the second load control device 720 may beconfigured to be aware of whether the first lamp 715 electricallyconnected to the first load control device 710 is on or off. In such aconfiguration, the first and second load control devices 710, 720 mayoperate to ensure that the first and second lamps 715, 725 are kept insync with one another, for example responsive to one or more change ofstate signals transmitted by the state change device 730.

The second load control device 720 is electrically connected to anelectrical circuit 750 that includes an alternating current (AC) powersource 751 and an electrical outlet 752 electrically connected to the ACpower source 751. The AC power source 751 may be, for example, the ACpower source 741. The outlet 752 includes two unswitched receptacles754. The second load control device 720 includes a plug 722 that isplugged into one of the unswitched receptacles 754 of the outlet 752 andthe second lamp 725 includes a plug 727 that is plugged into the plug722 of the second load control device 720. The lighting control system700 need not include the illustrated second load control device 720and/or the second lamp 725. Furthermore, lighting control system 700 mayinclude more or fewer load control devices that are associated with, forexample configured to be controlled by, the state change device 730.Each of the more or fewer load control devices may be electricallyconnected to respective electrical devices.

The lighting control system 700 may also include one or more otherdevices configured to wirelessly communicate with one or both of thefirst and second load control devices 710, 720. As shown, the lightingcontrol system 700 includes an occupancy and/or vacancy sensor 770, adaylight sensor 775, and a remote control 780, such as a remote keypad.The occupancy and/or vacancy sensor 770, the daylight sensor 775, and/orthe remote control 780 may wirelessly communicate with one or both ofthe first and second load control devices 710, 720, for example using RFsignals 760. For example, the occupancy and/or vacancy sensor 770, thedaylight sensor 775, and/or the remote control 780 may wirelesslycommunicate commands to one or both of the first and second load controldevices 710, 720 (e.g., turn on, turn off, or dim one or both of thefirst lamp 715 or the second lamp 725).

FIG. 9 depicts an example state change device 830. The state changedevice 830 may be deployed, for example, as the state change device 730as depicted in FIG. 8. The state change device 830 includes a housing834 that may be made of any suitable material, such as plastic. Thehousing 834 may enclose one or more electrical components of the statechange device 830. The state change device 830 includes a pair ofunswitched receptacles 832. As shown, the unswitched receptacles 832extend into an outward facing surface 835 of the housing 834. One orboth of the unswitched receptacles 832 may alternatively extend into anyother surface of the housing 834, for example into one or more sidesurfaces of the housing 834. The state change device 830 may beconfigured to be placed into electrical communication with an electricalcircuit, for example the electrical circuit 740. As shown, the statechange device 830 includes two plugs. Each plug includes a pair ofblades 836 and a ground pin 837 that protrude inward from the housing834. The blades 836 and ground pins 837 are configured to be insertedinto the receptacles of a standard electrical outlet, for example theswitched and unswitched receptacles 743, 744 of the outlet 742. Thestate change device 830 may define a control interface that isaccessible to a user of the state change device 830. For example, theillustrated state change device 830 includes a plurality of buttons 838that protrude through a side of the housing 834. Each of the buttons 838may be associated with one or more functions of the state change device830. The state change device 830 may include a selector switch (notshown) that is configured to indicate to the state change device 830which receptacle of an outlet that the state change device 830 isplugged into is the switched receptacle. Alternatively, the state changedevice 830 may be configured to detect (e.g., automatically detect)which receptacle of an outlet that the state change device 830 isplugged into is the switched receptacle.

FIG. 10 is a simplified block diagram of an example state change device900 that may be implemented as, for example, the state change device 730illustrated in FIG. 8 or the state change device 830 illustrated in FIG.9. As shown, the state change device 900 includes a first hot interminal 902 that is a switched hot terminal, a second hot in terminal904 that is an unswitched hot terminal, and respective first and secondneutral in terminals 906, 908 that are configured to be electricallyconnected to respective switched and unswitched receptacles of an outletpowered by an alternating current (AC) power source 910. The switchedreceptacle may be controlled by a switch 912, such as a wall-mountedswitch.

The state change device 900 includes first and second hot out terminals914, 916 and respective first and second neutral out terminals 918, 920that are configured to be facilitate the electrical connection of one ormore electrical devices to the state change device 900. The first andsecond hot out terminals 914, 916 and the first and second neutral outterminals 918, 920 may be electrically connected to, for example, theunswitched receptacles 832 of the state change device 830.

The state change device 900 includes a control circuit, for example acontroller 922, that is configured to control one or more functions ofthe state change device 900. The controller 922 may include one or morecomponents, such as processors (e.g., microprocessors),microcontrollers, integrated circuits (e.g., field programmable gatearrays), or the like, in any combination. For example, the controller922 may include a processor (not shown) that may executecomputer-executable instructions in order to control one or morefunctional aspects of the state change device 900.

The state change device 900 includes a power sensing circuit 924 that iselectrically connected between the first hot in terminal 902 and thefirst neutral in terminal 906, and is communicatively coupled to thecontroller 922. The power sensing circuit 924 is configured to sensewhen power is applied to the first hot in terminal 902 and the firstneutral in terminal 906, for example when the switch 912 is closed. Thepower sensing circuit 924 may provide one or more signals to thecontroller 922 that are indicative of whether power is applied to (e.g.,present at) a switched receptacle to which the state change device 900is electrically connected, for example the switched receptacle 743 ofthe outlet 742. For example, the power sensing circuit 924 may provide asignal to the controller 922 when the switch 912 is operated from theopen position to the closed position. The signal may be indicative ofpower being applied at the switched receptacle 743. The power sensingcircuit 924 may provide a signal to the controller 922 when the switch912 is operated from the closed position to the open position. Thesignal may be indicative of power being removed from the switchedreceptacle 743.

The state change device 900 includes a memory 926. The memory 926 may becommunicatively coupled to the controller 922 and may operate to storeinformation such as computer-executable instructions, configurationsettings associated with operation of the state change device 900, alast known state of one or more devices associated with the state changedevice 900, or the like. The memory 926 may include any componentsuitable for storing the information. For example, the memory 926 mayinclude one or more components of volatile and/or non-volatile memory,in any combination. The memory 926 may be internal and/or external withrespect to the controller 922. For example, the memory 926 and thecontroller 922 may be integrated within a microchip. During operation ofthe state change device 900, the controller 922 may store and/orretrieve information, for instance the computer-executable instructions,from the memory 926. It should be appreciated that functionality of thecontroller 922 may include any combination of hardware, firmware, and/orsoftware.

The state change device 900 includes a control interface 928 that may beoperated, for example, by a user of the state change device 900. Asshown, the control interface 928 includes one or more actuators 930 thatmay be, for example, the buttons 838 of the state change device 830, andone or more visual indicators 932, for example light emitting diodes(LEDs). Each actuator 930 may be associated with a respective visualindicator 932, for example. The control interface 928 may provide one ormore inputs to the controller 922, for example a signal indicative ofactuation of a corresponding one of the actuators 930. The controlinterface 928 may receive one or more inputs from the controller 922,for example commands to cause one or more of the visual indicators 932to illuminate.

The state change device 900 may include a wireless communication circuit934 that is communicatively coupled to the controller 922. The wirelesscommunication circuit 934 may include, for example, an RF communicationcircuit coupled to an antenna 936. The wireless communication circuit934 may include one or more components operable for the transmissionand/or reception of information that may include signals and/or data.For instance, the wireless communication circuit 934 may include an RFtransceiver, an RF transmitter, an RF receiver, an infrared (IR)transmitter, an IR receiver, a modem, and/or the like. The controller922 may be configured to transmit information via the wirelesscommunication circuit 934, for example a signal indicative of a changeof state of the state change device 900 such as the application of powerto or the removal of power from a switched receptacle to which the statechange device 900 is electrically connected. The wireless communicationcircuit 934 may be configured with capabilities to transmit informationin accordance with one or more communication schemes. For example, thewireless communication circuit 934 may be configured to be capable oftransmitting information via RF communication.

The state change device 900 may include a power supply 938 configured tosupply power to one or more components of the state change device 900.The power supply 938 is electrically connected between the second hot interminal 904 and the second neutral in terminal 908, and thus maycontinuously derive power from the unswitched receptacle 744 of theoutlet 742.

The state change device 900 may include a manual selector switch (notshown) that is configured to indicate to the state change device 900which receptacle of an outlet that the state change device 900 isplugged into is the switched receptacle. The selector switch may beconfigured to swap the electrical connections of the first hot interminal 902 and the second hot in terminal 904 and to swap theelectrical connections of the first and second neutral in terminals 906,908.

Alternatively, the state change device 900 may be configured to detect(e.g., automatically detect) which receptacle of an outlet that thestate change device 900 is plugged into is the switched receptacle. Toenable such autodetection, the state change device 900 may include asecond power sensing circuit (not shown) that is electrically connectedbetween the second hot in terminal 904 and the second neutral interminal 908 and is communicatively coupled to the controller 922. Thecontroller 922 may be configured to determine which one of the first orsecond power sensing circuits is supplied with constant power, and basedupon that determination, to respond to signals transmitted from theother of the first or second power sensing circuits that is not suppliedwith constant power. In accordance with such a configuration of thestate change device 900, the power supply 938 may be appropriatelycoupled to both the first and second hot in terminals 902, 904 to drawcurrent from the unswitched receptacle of the outlet.

It should be appreciated that one or more of the above-describedcomponents of the state change device 900, such as the power sensingcircuit 924, the memory 926, and/or the wireless communication circuit934, may be at least partially integrated with (e.g., completelyintegrated with) the controller 922, for example within a singlemicrochip, such as an integrated circuit.

FIG. 11 is a functional diagram illustrating an example operationprocess 1000 of a state change device, for example the state changedevice 730, 830, or 900, when power is applied to a switched ACreceptacle to which the state change device is electrically connected,for example the switched receptacle 743 of the outlet 742.

The operation process 1000 begins at 1002, when power is applied to theswitched receptacle to which the state change device, for example thestate change device 900, is electrically connected. At 1004, the powersensing circuit 924 determines that power has been supplied to theswitched receptacle. The power sensing circuit 924 may detect thepresence of power at the switched receptacle. The power sensing circuit924 may, responsive to detecting power at the switched receptacle,provide a signal to the controller 922 that indicates power has beenapplied at the switched receptacle. The power sensing circuit 924 maycontinue to send signals to the controller 922 to indicate the continuedpresence of power at the switched receptacle.

At 1006, the controller 922 may receive one or more signals from thepower sensing circuit 924 indicating that power has been applied at theswitched receptacle. The controller 922 may then wait until apredetermined amount of time has elapsed. The predetermined amount oftime may be a state of change threshold time, upon expiration of whichthe controller 922 may trigger the wireless communication circuit 934 totransmit a signal indicative of a change of state of the state changedevice 900. The signal may indicate, for example, that the state of thestate change device 900 has changed from an off state to an on state.The controller 922 may cause the wireless communication circuit 934 totransmit the signal via the antenna 936. The controller 922 may causethe wireless communication circuit 934 to transmit the signal one ormore times, for example in accordance with a configuration setting thatis stored in the memory 926 and retrieved by the controller 922.

The one or more signals may be broadcast to one or more devices that areassociated with the state change device 900. For example, with referenceto the example lighting control system 700 depicted in FIG. 8, the statechange device 830 may broadcast the signal to the first and second loadcontrol devices 710, 720 via RF signals 760.

At 1008, upon receiving the signal, the first and second load controldevices 710, 720 may determine whether to change the states ofrespective electrical loads electrically connected to the first andsecond load control devices 710, 720, for example the first and secondlamps 715, 725. For example, the first and second load control devices710, 720 may receive one or more forwarded change of state signalstransmitted by the state change device 730, or may receive respectivecommands, for example transmitted by a master device in the lightingcontrol system 700 responsive to one or more change of state signalstransmitted by the state change device 730. The commands may, forexample, direct the first and second load control devices 710, 720 tochange the states of the first and second lamps 715, 725. Alternatively,the determination may be based, for example, upon a last known state ofthe first and second lamps 715, 725. Based upon the determinations, thefirst and second load control devices 710, 720, may initiate statechanges for the first and second lamps 715, 725. For example, the firstload control device 710 may cause the first lamp 715 to operate from anoff state to an on state and the second load control device 720 maycause the second lamp 725 to operate from an off state to an on state.

At 1010, the one or more associated devices, for example the first andsecond load control devices 710, 720, may forward the signal to one ormore other devices associated with the first and second load controldevices 710, 720. For example, if the first load control device 710 isoperating as a master of the lighting control system 700, the first loadcontrol device 710 may forward the signal to the second load controldevice 720 and/or to one or more other devices associated with thelighting control system 700, or may issue a command to the second loadcontrol device 720 to change the state of the second lamp 725 (e.g.,turn the second lamp 725 on, turn the second lamp 725 off, or dim thesecond lamp 725). Similarly, if the second load control device 720 isoperating as a master of the lighting control system 700, the secondload control device 720 may forward the signal to the first load controldevice 710 and/or to one or more other devices associated with thelighting control system 700, or may issue a command to the first loadcontrol device 710 to change the state of the first lamp 715 (e.g., turnthe first lamp 715 on, turn the first lamp 715 off, or dim the firstlamp 715). After 1010, the operation process 1000 may conclude. Itshould be appreciated that 1010 is optional, for example in accordancewith whether or not one of the first or second load control devices 710,720 is operating as a master of the lighting control system 700. Forexample, if neither of the first or second load control devices 710, 720are operating as a master in the lighting control system 700, theoperation process 1000 may conclude after 1008, when the first andsecond load control devices 710, 720 have received and/or processed thesignal.

FIG. 12 is a functional diagram illustrating an example operationprocess 1100 of a state change device, for example the state changedevices 730, 830 or 900, when power is removed from a switched ACreceptacle to which the state change device is electrically connected,for example the switched receptacle 743 of the outlet 742.

The operation process 1100 begins at 1102, when power is removed fromthe switched receptacle to which the state change device, for examplethe state change device 900, is electrically connected. At 1104, thepower sensing circuit 924 determines that power has been removed fromthe switched receptacle. The power sensing circuit 924 may detect theabsence of power at the switched receptacle. The power sensing circuit924 may, responsive to detecting the lack of power at the switchedreceptacle, provide a signal to the controller 922 that indicates powerhas been removed from the switched receptacle. Alternatively, the powersensing circuit 924 may cease sending signals to the controller 922 thatindicate the continued presence of power at the switched receptacle.

At 1106, the controller 922 may receive one or more signals from thepower sensing circuit 924 indicating that power has been removed fromthe switched receptacle. The controller 922 may then determine whetherpower has actually been removed or whether a line disturbance hasoccurred. The controller 922 may make this determination, for example,by waiting for a predetermined interval of time and listening for one ormore signals from the power sensing circuit 924 that indicate that powerhas been applied at the switched receptacle. If the controller 922receives one or more such signals, the controller 922 may determine thata line disturbance has occurred and the operation process 1100 mayconclude. If predetermined interval expires and the controller 922 hasnot received one or more such signals, the controller 922 may determinethat power has been removed from the switched receptacle.

At 1108, after determining that power has been removed from the switchedreceptacle, the controller 922 may trigger the wireless communicationcircuit 934 to transmit a signal indicative of a change of state of thestate change device 900. The signal may indicate, for example, that thestate of the state change device 900 has changed from an on state to anoff state. The controller 922 may cause the wireless communicationcircuit 934 to transmit the signal via the antenna 936. The controller922 may cause the wireless communication circuit 934 to transmit thesignal one or more times, for example in accordance with a configurationsetting stored in the memory 926 and is retrieved by the controller 922.

The one or more signals may be broadcast to one or more devices that areassociated with the state change device 900. For example, with referenceto the example lighting control system 700 depicted in FIG. 8, the statechange device 830 may broadcast the signal to the first and second loadcontrol devices 710, 720 via RF signals 760.

At 1110, upon receiving the signal, the first and second load controldevices 710, 720 may determine whether to change the states ofrespective electrical loads electrically connected to the first andsecond load control devices 710, 720, for example the first and secondlamps 715, 725. For example, the first and second load control devices710, 720 may receive one or more forwarded change of state signalstransmitted by the state change device 730, or may receive respectivecommands, for example transmitted by a master device in the lightingcontrol system 700 responsive to one or more change of state signalstransmitted by the state change device 730. The commands may, forexample, direct the first and second load control devices 710, 720 tochange the states of the first and second lamps 715, 725. Alternatively,the determination may be based, for example, upon a last known state ofthe first and second lamps 715, 725. Based upon the determinations, thefirst and second load control devices 710, 720, may initiate statechanges for the first and second lamps 715, 725. For example, the firstload control device 710 may cause the first lamp 715 to operate from anon state to an off state and the second load control device 720 maycause the second lamp 725 to operate from an on state to an off state.

At 1112, the one or more associated devices, for example the first andsecond load control devices 710, 720, may forward the signal to one ormore other devices associated with the first and second load controldevices 710, 720. For example, if the first load control device 710 isoperating as a master of the lighting control system 700, the first loadcontrol device 710 may forward the signal to the second load controldevice 720 and/or to one or more other devices associated with thelighting control system 700, or may issue a command to the second loadcontrol device 720 to change the state of the second lamp 725 (e.g.,turn the second lamp 725 on, turn the second lamp 725 off, or dim thesecond lamp 725). Similarly, if the second load control device 720 isoperating as a master of the lighting control system 700, the secondload control device 720 may forward the signal to the first load controldevice 710 and/or to one or more other devices associated with thelighting control system 700, or may issue a command to the first loadcontrol device 710 to change the state of the first lamp 715 (e.g., turnthe first lamp 715 on, turn the first lamp 715 off, or dim the firstlamp 715). After 1112, the operation process 1100 may conclude. Itshould be appreciated that 1112 is optional, for example in accordancewith whether or not one of the first or second load control devices 710,720 is operating as a master of the lighting control system 700. Forexample, if neither of the first or second load control devices 710, 720are operating as a master in the lighting control system 700, theoperation process 1100 may conclude after 1110, when the first andsecond load control devices 710, 720 have received and/or processed thesignal.

FIG. 13 depicts an example load control system. As shown, the loadcontrol system is a lighting control system 1200. The lighting controlsystem 1200 includes a load control device 1210 and a device that may bereferred to as a state change device 1230 or a state change controller.The state change device 1230 is configured to send signals to and/orreceive signals from the load control device 1210 via wirelesscommunication. The state change device 1230 is plugged into both theswitched receptacle 1243 and the unswitched receptacle 1244 of an outlet1242. The state change device 1230 will be continuously powered by theunswitched receptacle 1244. The state change device 1230 includes a pairof receptacles 1232. The state change device 1230 includes a loadcontrol circuit, such that the state change device 1230 may function asa load control device. A first one of the receptacles 1232 iselectrically connected to the load control circuit, and is configured asa dimmed receptacle 1231. A second one of the receptacles 1232 isconfigured as an unswitched receptacle 1233.

The lighting control system 1200 further includes a first lamp 1215electrically connected to, for example plugged into, the state changedevice 1230, such that the state change device 1230 controls the amountof power delivered to the first lamp 1215. As shown, the load controldevice 1210 is a table top RF dimmer switch. The lighting control system1200 further includes a second lamp 1225 electrically connected to, forexample plugged into, the load control device 1210, such that the loadcontrol device 1210 controls the amount of power delivered to the secondlamp 1225.

The state change device 1230 may be configured to transmit and/orreceive the signals, for example, via radio-frequency (RF) communicationsignals 1260. The state change device 1230 may transmit signals to theload control device 1210, for example. The signals may be indicative ofa change of state within the lighting control system 1200, for exampleindicative of a change of state at a switched receptacle that the statechange device 1230 is electrically connected to. Such signals may bereferred to as change of state signals, and may be interpreted by one ormore devices associated with the state change device 1230, for examplethe load control device 1210, as indications to turn on, turn off, dim,etc. respective electrical loads electrically connected to the loadcontrol device 1210.

The state change device 1230 is electrically connected to an electricalcircuit 1240 that includes an alternating current (AC) power source 1241and an electrical outlet 1242 electrically connected to the AC powersource 1241. The outlet 1242 includes a switched receptacle 1243 and anunswitched receptacle 1244. The state change device 1230 is electricallyconnected to, for example plugged into, the switched receptacle 1243 andthe unswitched receptacle 1244. The electrical circuit 1240 alsoincludes a wall-mounted switch 1246 that is coupled in series electricalconnection between the AC power source 1241 and the switched receptacle1243.

The state change device 1230 may derive power from the unswitchedreceptacle 1244, regardless of whether power is applied to the switchedreceptacle 1243, for example whether the wall-mounted switch 1246 is inthe on position or the off position. The state change device 1230includes a pair of receptacles 1232. The state change device 1230 is notlimited to two receptacles 1232 as illustrated, and may include more orfewer than two receptacles. As shown, the receptacles 1232 areconfigured as a dimmed receptacle 1231 and an unswitched receptacle1233. The first lamp 1215 includes a plug 1217 that is plugged into thedimmed receptacle 1231 of the state change device 1230, such that thefirst lamp 1215 may be switched by the wall-mounted switch 1246 anddimmed by the load control circuit of the state change device 1230.

The state change device 1230 may transmit signals responsive to deliveryor removal of power to the switched receptacle 1243 of the outlet 1242.When the wall-mounted switch 1246 is operated from the off position tothe on position, power may be delivered to the switched receptacle 1243.The state change device 1230 may sense the presence of power at theswitched receptacle 1243, and may transmit one or more signals, forexample via RF signals 1260, to the load control device 1210. Thesignals may be indicative of a change of state in the lighting controlsystem 1200. The one or more signals may be received at the load controldevice 1210. Responsive to receipt of the signals, the load controldevice 1210 may change the state of the second lamp 1225. For example,the load control device 1210 may change the state of the second lamp1225 from off to on.

When the wall-mounted switch 1246 is operated from the on position tothe off position, power may be removed from the switched receptacle1243. The state change device 1230 may sense the removal of power fromthe switched receptacle 1243, and may transmit one or more signals, forexample via RF signals 1260, to the load control device 1210. Thesignals may be indicative of a change of state in the lighting controlsystem 1200. The one or more signals may be received at the load controldevice 1210. Responsive to receipt of the signals, the load controldevice 1210 may change the state of the second lamp 1225. For example,the load control device 1210 may change the state of the second lamp1225 from on to off.

The one or more signals transmitted by the state change device 1230, forexample responsive to operation of the wall-mounted switch 1246 from theon position to the off position or from the off position to the onposition, are not limited to indicating a change of state in thelighting control system 1200. For example, one or more signalstransmitted by the state change device 1230, for example responsive tooperation of the wall-mounted switch 1246, may be indicative of a loadcontrol scene (e.g., a lighting scene or preset) to be applied to one ormore electrical loads (e.g., the first and second lamps 1215, 1225) ofthe lighting control system 1200. A lighting scene may includerespective predetermined states that are to be assumed by one or morelighting loads of the lighting control system 1200. For example, alighting scene may include one or both of the first and second lamps1215, 1225 in the off state, may include one or both of the first andsecond lamps 1215, 1225 in the on state, may include one or both of thefirst and second lamps 1215, 1225 dimmed to a select dimming level, orany combination of thereof.

Respective signals indicative of one or more load control scenes may betransmitted, for example, in accordance with a number of times that thewall-mounted switch 1246 is operated from one state to the other (e.g.,from off to on or from on to off) within a prescribed amount of time.For example, the state change device 1230 may be configured to generateand transmit one or more change of state signals if the wall-mountedswitch 1246 is operated from one state to the other once during theprescribed amount of time, may be configured to generate and transmitone or more signals indicative of a first lighting scene if thewall-mounted switch 1246 is operated from one state to the other twiceduring the prescribed amount of time, may be configured to generate andtransmit one or more signals indicative of a second lighting scene ifthe wall-mounted switch 1246 is operated from one state to the otherthree times during the prescribed amount of time, and so on.

The state change device 1230 may be deployed in a load control systemthat includes one or more load control devices and/or associatedelectrical loads in addition to the state change device 1230, such asthe lighting control system 1200 depicted in FIG. 13. One of the loadcontrol devices, for example the state change device 1230 or the loadcontrol device 1210, may be configured to operate as a control entity,such as a master device, within the lighting control system 1200.

The master device, or master, may operate to at least partially controlfunctionality of the other load control devices of the load controlsystem. The other load control devices of the load control system may beconfigured to assume subservient roles to the master device, such thatthe subservient devices will perform commands issued by the master. Itshould be appreciated that if the load control system includes only oneload control device, the load control system may not include a master.

One of the load control devices may be designated as the master, forexample by a user of the load control system. Alternatively, one of theload control devices may assume the role of the master. For example,upon association with the load control system, a load control device maypoll the other load control devices of the load control system, forexample via broadcast, to determine if the load control system currentlyhas a master. If the polling load control device does not receive ananswer that another device of the load control system is the master, thepolling load control device may assume the role of the master in theload control system.

The master load control device may be configured to observe and/orrecord present state information pertaining to one or more subservientload control devices of the load control system. In an example, withreference to the lighting control system 1200 shown in FIG. 13, thestate change device 1230 may assume the role of master and the loadcontrol device 1210 may assume a subservient role to the state changedevice 1230, such that the state change device 1230 is able to at leastpartially control operation of the load control device 1210. The statechange device 1230 may observe and/or record present state information,for example last known state information, pertaining to the load controldevice 1210 and/or to an electrical load electrically connected to theload control device 1210, for example information pertaining to a lastknown state of the second lamp 1225 (e.g., whether the second lamp 1225is on or off).

The state change device 1230, in the role of master in the lightingcontrol system 1200, may be configured such that if at least onelighting load, for example the first lamp 1215 or the second lamp 1225,is in an on state when the state change device 1230 transmits one ormore change of state signals, one or more of the other lighting loads ofthe lighting control system 1200 (e.g., each of the other lightingloads) will be operated from the on state to the off state or left inthe off state. For example, if the first lamp 1215 is off and the secondlamp 1225 is on when the wall-mounted switch 1246 is operated, the statechange device 1230 will not change the state of the first lamp 1215 andwill transmit one or more change of state signals or an appropriatecommand, for example a command to turn the second lamp 1225 off, to theload control device 1210. The load control device 1210, upon receipt ofthe one or more change of state signals or the command, will change thestate of the second lamp 1225 from on to off.

Alternatively, the state change device 1230, in the role of master inthe lighting control system 1200, may be configured to maintainsynchronization of the lighting loads of the lighting control system1200. For example, if the state of the first lamp 1215 is changedlocally at the state change device 1230, the state change device 1230may transmit a command to the load control device 1210 that will causeload control device 1210 to change the state of the second lamp 1225,thus keeping the states of the first and second lamps 1215, 1225, syncedto one another. If the state of the second lamp 1225 is changed locallyat the load control device 1210, the state change device 1230 may changethe state of the first lamp 1215, thus keeping the states of the firstand second lamps 1215, 1225, synced to one another.

When the wall-mounted switch 1246 is operated, the state change device1230 will change the state of the first lamp 1215, for example from onto off or from off to on, and may transmit one or more change of statesignals that may be received by the load control device 1210. The loadcontrol device 1210 may ignore the one or more change of state signalsfrom the state change device 1230, for example in accordance with thesubservient role the load control device 1210 has with respect to thestate change device 1230. Alternatively, the state change device 1230will change the state of the first lamp 1215, for example from on to offor from off to on, and may transmit an appropriate command, for exampleto turn the second lamp 1225 on or off, to the load control device 1210.The load control device 1210, upon receipt of the one or more change ofstate signals or the command, will change the state of the second lamp1225, for example from on to off or from off to on, such that the statesof the first and second lamps 1215, 1225 are kept in sync.

The role of master in a load control system in which the state changedevice 1230 is deployed, for example the lighting control system 1200,need not be fulfilled by a load control device of the load controlsystem, for example the state change device 1230 or the load controldevice 1210. Such a load control system may include another deviceconfigured to fulfill the role of master, for example a centralcontroller, a main repeater, or the like. In such a configuration, oneor more load control devices of the load control system, for example thestate change device 1230 or the load control device 1210, may beconfigured to assume subservient roles to the master, and the master maybe configured to observe and/or record present state informationpertaining to the subservient load control devices of the load controlsystem. The subservient load control devices may be configured to ignorechange of state signals transmitted by the state change device 1230 andthe master may be configured to forward change of state signals receivedfrom the state change device 1230 to the subservient load controldevices, or may, upon receipt of one or more change of state signalsfrom the state change device 1230, transmit appropriate commands to thesubservient load control devices.

A load control system in which the state change device 1230 is deployed,for example the lighting control system 1200, need not include a centralcontrol entity, such as a master. For example, one or more load controldevices associated with the load control system, for example the statechange device 1230 and the load control device 1210, may be configuredto be aware of present state information pertaining to the other loadcontrol devices of the lighting control system 1200. For example, thestate change device 1230 may be configured to be aware of whether thesecond lamp 1225 electrically connected to the load control device 1210is on or off. Similarly, the load control device 1210 may be configuredto be aware of whether the first lamp 1215 electrically connected to thestate change device 1230 is on or off. In such a configuration, thestate change device 1230 and the load control device 1210 may operate toensure that the first and second lamps 1215, 1225 are kept in sync withone another.

The load control device 1210 is electrically connected to an electricalcircuit 1250 that includes an alternating current (AC) power source 1251and an electrical outlet 1252 electrically connected to the AC powersource 1251. The AC power source 1251 may be, for example, the AC powersource 1241. The outlet 1252 includes two unswitched receptacles 1254.The load control device 1210 includes a plug 1212 that is plugged intoone of the unswitched receptacles 1254 of the outlet 1252 and the secondlamp 1225 includes a plug 1227 that is plugged into the plug 1212 of theload control device 1210. The lighting control system 1200 need notinclude the illustrated load control device 1210 and/or the second lamp1225. Furthermore, lighting control system 1200 may include more orfewer load control devices that are associated with, for exampleconfigured to be controlled by, the state change device 1230. Each ofthe more or fewer load control devices may be electrically connected torespective electrical devices.

The lighting control system 1200 may also include one or more otherdevices configured to wirelessly communicate with one or both of theload control device 1210 and the state change device 1230. As shown, thelighting control system 1200 includes an occupancy and/or vacancy sensor1270, a daylight sensor 1275, and a remote control 1280, such as aremote keypad. The occupancy and/or vacancy sensor 1270, the daylightsensor 1275, and/or the remote control 1280 may wirelessly communicatewith one or both of the load control device 1210 and the state changedevice 1230, for example using RF signals 1260. For example, theoccupancy and/or vacancy sensor 1270, the daylight sensor 1275, and/theor remote control 1280 may wirelessly communicate commands to one orboth of the load control device 1210 and the state change device 1230(e.g., turn on, turn off, or dim one or both of the first lamp 1215 orthe second lamp 1225).

If the state change device 1230 assumes a subservient role to anotherdevice of the lighting control system 1200, for example the load controldevice 1210, the state change device 1230 may be configured to receivecommands from one or more other devices of the lighting control system1200. For example, the state change device 1230 may receive commandsfrom the load control device 1210, the occupancy and/or vacancy sensor1270, the daylight sensor 1275, and/or the remote control 1280, forexample via RF signals 1260. The state change device 1230 may beconfigured to execute received commands. The state change device 1230may be configured to evaluate received commands. For example, the statechange device 1230 may compare one or more received commands against apresent state of one or more devices electrically connected to the statechange device 1230, such as the first lamp 1215. The state change device1230 may be configured to, based on the evaluation of the one or morereceived commands, follow or ignore respective ones of the one or morereceived commands.

FIG. 14 depicts an example state change device 1330. The state changedevice 1330 may be deployed, for example, as the state change device1230 as depicted in FIG. 13. The state change device 1330 includes ahousing 1334 that may be made of any suitable material, such as plastic.The housing 1334 may enclose one or more electrical components of thestate change device 1330. The state change device 1330 includes a pairof receptacles 1332. A first one of the receptacles 1332 is configuredas a dimmed receptacle 1331 and a second one of the receptacles 1332 isconfigured as an unswitched receptacle 1333. The dimmed receptacle 1331may not have an opening to receive a ground pin of a grounded plug, andmay be marked to identify the receptacle as a dimmed receptacle. Asshown, the receptacles 1332 extend into an outward facing surface 1335of the housing 1334. One or both of the receptacles 1332 mayalternatively extend into any other surface of the housing 1334, forexample into one or more side surfaces of the housing 1334. The statechange device 1330 may be configured to be placed into electricalcommunication with an electrical circuit, for example the electricalcircuit 1240. As shown, the state change device 1330 includes two plugs.Each plug includes a pair of blades 1336 and a ground pin 1337 thatprotrude inward from the housing 1334. The blades 1336 and ground pins1337 are configured to be inserted into the receptacles of a standardelectrical outlet, for example the switched and unswitched receptacles1243, 1244 of the outlet 1242. The state change device 1330 may define acontrol interface that is accessible to a user of the state changedevice 1330. For example, the illustrated state change device 1330includes a plurality of buttons 1338 that protrude through a side of thehousing 1334. Each of the buttons 1338 may be associated with one ormore functions of the state change device 1330. The state change device1330 may include a selector switch (not shown) that is configured toindicate to the state change device 1330 which receptacle of an outletthat the state change device 1330 is plugged into is the switchedreceptacle. Alternatively, the state change device 1330 may beconfigured to detect (e.g., automatically detect) which receptacle of anoutlet that the state change device 1330 is plugged into is the switchedreceptacle.

FIG. 15 is a simplified block diagram of an example state change device1400 that may be implemented as, for example, the state change device1230 illustrated in FIG. 13 of the state change device 1330 illustratedin FIG. 14. As shown, the state change device 1400 includes a first hotin terminal 1402 that is a switched hot terminal, a second hot interminal 1404 that is an unswitched hot terminal, and respective firstand second neutral in terminals 1406, 1408 that are configured to beelectrically connected to respective switched and unswitched receptaclesof an outlet powered by an alternating current (AC) power source 1410.The switched receptacle may be controlled by a switch 1412, such as awall-mounted switch.

The state change device 1400 includes first and second hot out terminals1414, 1416 and respective first and second neutral out terminals 1418,1420 that are configured to be facilitate the electrical connection ofone or more electrical devices to the state change device 1400. Thefirst and second hot out terminals 1414, 1416 and the first and secondneutral out terminals 1418, 1420 may be electrically connected to, forexample, the dimmed and unswitched receptacles 1331, 1333, respectively,of the state change device 1330.

The state change device 1400 includes a control circuit, for example acontroller 1422, that is configured to control one or more functions ofthe state change device 1400. The controller 1422 may include one ormore components, such as processors (e.g., microprocessors),microcontrollers, integrated circuits (e.g., field programmable gatearrays), or the like, in any combination. For example, the controller1422 may include a processor (not shown) that may executecomputer-executable instructions in order to control one or morefunctional aspects of the state change device 1400.

The state change device 1400 includes a power sensing circuit 1424 thatis electrically connected between the first hot in terminal 1402 and thefirst neutral in terminal 1406, and is communicatively coupled to thecontroller 1422. The power sensing circuit 1424 is configured to sensewhen power is applied to the first hot in terminal 1402 and the firstneutral in terminal 1406, for example when the switch 1412 is closed.The power sensing circuit 1424 may provide one or more signals to thecontroller 1422 that are indicative of whether power is applied to(e.g., present at) a switched receptacle to which the state changedevice 1400 is electrically connected, for example the switchedreceptacle 1243 of the outlet 1242. For example, the power sensingcircuit 1424 may provide a signal to the controller 1422 when the switch1412 is operated from the open position to the closed position. Thesignal may be indicative of power being applied at the switchedreceptacle 1243. The power sensing circuit 1424 may provide a signal tothe controller 1422 when the switch 1412 is operated from the closedposition to the open position. The signal may be indicative of powerbeing removed from the switched receptacle 1243.

The state change device 1400 includes a load control circuit 1426 thatis electrically connected between the first hot out terminal 1414 andthe first neutral out terminal 1418. The load control circuit 1426 maybe used to control the amount of power delivered to an electrical loadelectrically connected to the first hot out terminal 1414 and the firstneutral out terminal 1418, for example a lighting load plugged into thedimmed receptacle 1331 of the state change device 1330. In this regard,the state change device 1400 can be configured to function as a loadcontrol device.

The load control circuit 1426 includes a controllably conductive device(not shown in FIG. 15), a drive circuit (not shown in FIG. 15), and azero-cross detection circuit (not shown in FIG. 15). The controllablyconductive device may be, for example, a bidirectional semiconductorswitch, such as a triac, that is configured to be electrically coupledbetween the AC power source 1410 and the electrical load (which may bereferred to as the load) electrically connected to the first hot outterminal 1414 and the first neutral out terminal 1418. The controllablyconductive device may be operable between a non-conductive state inwhich the gate is open such that AC from the AC power source 1410 is notdelivered to the load and a conductive state in which the gate is closedsuch that AC from the AC power source 1410 passes through thecontrollably conductive device and is delivered to the load. Thecontrollably conductive device may be referred to as “off” when in thenon-conductive state and “on” when in the conductive state.Alternatively, the controllably conductive device may be implemented asa relay or any suitable bidirectional semiconductors switch, such as,for example, a field-effect transistor (FET) in a rectifier bridge, twoFETs in anti-series connection, or one or more insulated-gate bipolarjunction transistors (IGBTs).

The drive circuit is electrically connected between the controller 1422and the controllably conductive device and is communicatively coupled tothe controller 1422. The drive circuit may include circuitry configuredto convert control signals issued by the controller 1422 into triggeringsignals that may trigger the controllably conductive device to operatebetween the non-conductive state and the conductive state. Thezero-cross detection circuit is configured to detect zero crossingevents associated with an AC waveform generated by the AC power source1410.

The controller 1422 may issue control signals to the drive circuit inaccordance with a prescribed interval. For example, the controller 1422may be made aware of a zero crossing event associated with an AC linevoltage generated by the AC power source 1410, for example via thezero-cross detection circuit. The controller 1422 may be configured to,upon detection of the zero crossing, issue a control signal to the drivecircuit to operate the controllably conductive device from theconductive state to the non-conductive state (i.e., to open the gate)for a duration of the prescribed interval and, upon expiration of theinterval, to operate the controllably conductive device from thenon-conductive state to the conductive state (i.e., to close the gate).The expiration of the interval may substantially coincide with asubsequent, consecutive zero crossing event associated with the ACwaveform generated by the AC power source 1410.

The state change device 1400 includes a memory 1428. The memory 1428 maybe communicatively coupled to the controller 1422 and may operate tostore information such as computer-executable instructions,configuration settings associated with operation of the state changedevice 1400, a last known state of one or more devices associated withthe state change device 1400, or the like. The memory 1428 may includeany component suitable for storing the information. For example, thememory 1428 may include one or more components of volatile and/ornon-volatile memory, in any combination. The memory 1428 may be internaland/or external with respect to the controller 1422. For example, thememory 1428 and the controller 1422 may be integrated within amicrochip. During operation of the state change device 1400, thecontroller 1422 may store and/or retrieve information, for instance thecomputer-executable instructions, from the memory 1428. It should beappreciated that functionality of the controller 1422 may include anycombination of hardware, firmware, and/or software.

The state change device 1400 includes a control interface 1430 that maybe operated, for example, by a user of the state change device 1400. Asshown, the control interface 1430 includes one or more actuators 1432that may be, for example, the buttons 1338 of the state change device1330, and one or more visual indicators 1434, for example light emittingdiodes (LEDs). Each actuator 1432 may be associated with a respectivevisual indicator 1434, for example. The control interface 1430 mayprovide one or more inputs to the controller 1422, for example a signalindicative of actuation of a corresponding one of the actuators 1432.The control interface 1430 may receive one or more inputs from thecontroller 1422, for example commands to cause one or more of the visualindicators 1434 to illuminate.

The state change device 1400 may include a wireless communicationcircuit 1436 that is communicatively coupled to the controller 1422. Thewireless communication circuit 1436 may include, for example, an RFcommunication circuit coupled to an antenna 1438. The wirelesscommunication circuit 1436 may include one or more components operablefor the transmission and/or reception of information that may includesignals and/or data. For instance, the wireless communication circuit1436 may include an RF transceiver, an RF transmitter, an RF receiver,an infrared (IR) transmitter, an IR receiver, a modem, and/or the like.The controller 1422 may be configured to transmit information via thewireless communication circuit 1436, for example a signal indicative ofa change of state of the state change device 1400, such as theapplication of power to or the removal of power from a switchedreceptacle to which the state change device 1400 is electricallyconnected. The wireless communication circuit 1436 may be configuredwith capabilities to transmit information in accordance with one or morecommunication schemes. For example, the wireless communication circuit1436 may be configured to be capable of transmitting information via RFcommunication.

The state change device 1400 may include a power supply 1440 configuredto supply power to one or more components of the state change device1400. The power supply 1440 is electrically connected between the secondhot in terminal 1404 and the second neutral in terminal 1408, and thusmay continuously derive power from the unswitched receptacle 1244 of theoutlet 1242.

The state change device 1400 may include a manual selector switch (notshown) that is configured to indicate to the state change device 1400which receptacle of an outlet that the state change device 1400 isplugged into is the switched receptacle. The selector switch may beconfigured to swap the electrical connections of the first hot interminal 1402 and the second hot in terminal 1404 and to swap theelectrical connections of the first and second neutral in terminals1406, 1408.

Alternatively, the state change device 1400 may be configured to detect(e.g., automatically detect) which receptacle of an outlet that thestate change device 1400 is plugged into is the switched receptacle. Toenable such autodetection, the state change device 1400 may include asecond power sensing circuit (not shown) that is electrically connectedbetween the second hot in terminal 1404 and the second neutral interminal 1408 and is communicatively coupled to the controller 1422. Thecontroller 1422 may be configured to determine which one of the first orsecond power sensing circuits is supplied with constant power, and basedupon that determination, to respond to signals transmitted from theother of the first or second power sensing circuits that is not suppliedwith constant power. In accordance with such a configuration of thestate change device 1400, the power supply 1440 may be appropriatelycoupled to both the first and second hot in terminals 1402, 1404 to drawcurrent from the unswitched receptacle of the outlet.

It should be appreciated that one or more of the above-describedcomponents of the state change device 1400, such as the power sensingcircuit 1424, the load control circuit 1426 (including one or morecomponents of the load control circuit 1426), the memory 1428, and/orthe wireless communication circuit 1436, may be at least partiallyintegrated with (e.g., completely integrated with) the controller 1422,for example within a single microchip, such as an integrated circuit.

It should be appreciated that the example state change devices, whileillustrated and described herein with reference to alternating currentbased load control systems, may also be configured for use with directcurrent based load control systems.

The invention claimed is:
 1. A device configured to be electricallyconnected to a switched alternating current (AC) receptacle, the devicecomprising: a sensing circuit that detects whether power is present atthe switched receptacle; a controller that is communicatively coupled tothe sensing circuit and configured to generate a signal that isindicative of a change of state of power being supplied at the switchedreceptacle; and a communication circuit that is configured for wirelesscommunication, wherein the controller causes the communication circuitto transmit the signal to one or more associated devices.
 2. The deviceof claim 1, further comprising a power supply configured to supply powerto the sensing circuit, the controller, and the communication circuit.3. The device of claim 2, wherein the power supply is transitory.
 4. Thedevice of claim 2, wherein the power supply is a capacitor configured tostore electricity supplied to the switched receptacle.
 5. The device ofclaim 4, wherein the capacitor is configured to store sufficientelectricity for the device to generate and transmit the signal oncepower is removed from the switched receptacle.
 6. The device of claim 1,further comprising a memory configured to store respective last knownstates of the one or more associated devices.
 7. The device of claim 1,wherein the one or more associated devices are load control devices. 8.The device of claim 1, further comprising a control interface.
 9. Thedevice of claim 8, further comprising a housing, wherein the controlinterface comprises a plurality of buttons that protrude through thehousing, the buttons configured to control respective functions of thedevice.
 10. The device of claim 9, wherein the control interface furthercomprises a plurality of visual indicators, each of the plurality ofvisual indicators corresponding to one of the plurality of buttons. 11.The device of claim 1, wherein the controller is further configured towait for a predetermined amount of time before generating the signal.12. A device configured to be electrically connected to a switchedalternating current (AC) receptacle, the device configured for wirelesscommunication with an associated load control device, the devicecomprising: a sensing circuit that is configured to detect an eventrepresentative of a change of state of power at the switched receptacle;a controller that is configured to generate a change of state signal fortransmission to the load control device; and a transmitter that isconfigured to transmit the signal based on the detection of the event.13. The device of claim 12, wherein the event is the application ofpower to the switched receptacle.
 14. The device of claim 12, whereinthe event is the removal of power from the switched receptacle.
 15. Thedevice of claim 12, wherein the sensing circuit is further configured toinform the controller of detection of the event.
 16. The device of claim15, wherein the controller causes the transmitter to transmit the signalresponsive to being informed of the detection of the event by thesensing circuit.
 17. The device of claim 12, further comprising a powersupply configured to, after the removal of power from the switchedreceptacle, supply an amount of voltage to the device sufficient for thedevice to generate and transmit the signal.
 18. The device of claim 17,wherein the power supply is a capacitor configured to store electricitywhen power is applied to the switched receptacle.
 19. The device ofclaim 12, further comprising a memory communicatively coupled to thecontroller, wherein the controller is configured to store a last knownstate of the load control device in the memory.
 20. The device of claim12, wherein the controller is further configured to wait for apredetermined amount of time before generating the signal.
 21. A loadcontrol system, the load control system comprising: a load controldevice configured for wireless communication, the load control devicefurther configured to control an amount of power delivered to anelectrical load electrically connected to the load control device; and astate change device configured for wireless communication and associatedwith the load control device, the state change device electricallyconnected to a switched receptacle of an outlet, the state change devicefurther configured to generate a signal indicative of a change of stateof power being supplied at the switched receptacle and to transmit thesignal to the load control device.
 22. The load control system of claim21, wherein the state change device performs a master role within theload control system and the load control device performs a subservientrole within the load control system.
 23. The load control system ofclaim 21, wherein the load control device performs a master role withinthe load control system and the state change device performs asubservient role within the load control system.
 24. The load controlsystem of claim 21, wherein the state change device comprises: a sensingcircuit that detects whether power is present at the switchedreceptacle; a controller that is communicatively coupled to the sensingcircuit and configured to generate a signal indicative of a statechange; and a communication circuit configured for wirelesscommunication, wherein the controller causes the communication circuitto transmit the signal to the load control device.
 25. The load controlsystem of claim 24, wherein the state change device further comprises apower supply electrically connected to the unswitched receptacle. 26.The load control system of claim 24, wherein the controller is furtherconfigured to, upon being informed by the sensing circuit of applicationof power to the switched receptacle, wait a predetermined interval oftime before causing the communication circuit to transmit the signal tothe load control device.
 27. The load control system of claim 24,wherein the controller is further configured to, upon being informed bythe sensing circuit of removal of power from the switched receptacle,wait a predetermined interval of time before causing the communicationcircuit to transmit the signal to the load control device.
 28. The loadcontrol system of claim 21, further comprising a pair of receptacleselectrically connected between the unswitched hot terminal and theunswitched neutral terminal.
 29. The load control system of claim 24,wherein the state change device is configured to issue commands to theload control device via radio frequency signals broadcast from thecommunication circuit.
 30. The load control system of claim 24, whereinthe state change device is configured to receive commands from the loadcontrol device via radio frequency signals received by the communicationcircuit.